Vapor-rectifier.



HAROLD A. NEWCOIVIB, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENN-1 SYLVANIA.

VAPOR-RECTIFIER.

Specification of Letters Iatent.

Patented Feb. 11, 1919.

Application filed May 6, 1915. Serial No. 26,291.

To all whom it may concern:

Be it known that I, HAROLD A. NEWCOMB, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Vapor-Rectifiers, of which the following is a specification. 1

My invention relates to vacuum electric apparatus, such, for example, as vapor-arc rectifiers and X-ray tubes, and it has for its object to provide means whereby arcs and electrical discharges may be readily controlled, in apparatus of the character specified.

The single figure of the accompanying drawing is a perspective View of a vapor-arc rectifier of the glass-container type embodying one form of my invention.

In the operation of vacuum electric apparatus, such, for example, as vapor-arc rectifiers, it is frequently essential that the discharge between two electrodes be forced to take an indirect path so that the discharge flow line shall not coincide with the electrostatic flow lines and so that particles of electrode material mechanically entrained by the arc blast at one electrode shall not be carried over to the other electrode. Shields for this purpose have been composed hitherto of glass or metal, preferably sheet iron, but have not given entire satisfaction because of failure under the excessive heat of rectifying arcs and because of the large amount of occluded gases given off, when highly heated. I have found that the material known as alundum, which is composed essentially of aluminum oxid and aluminum carbid synthetically joined in the electric furnace, is extremely well adapted for shielding purposes. It is very refractory and, furthermore, is of such a porous nature that it readily gives up its occluded gases in the pumping stage and liberates little or no gas in the su sequent operation of the device.

When it is desired to employ tungsten for leading-in wires, on account of the great expense of platinum, an almost perfect seal of said metal may be formed with sodium borosilicate glass, as set forth in my copending application, Serial No. 811, filed Jan. 6, 1915 and assigned to the Westinghouse Electric & Manufacturing Company. This good sealing depends upon the fact that tungsten and the glass mentioned have substantially the are set up which would lead to leaks and fractures.

It is frequently desirable to insert aporous plug 1n the wall of the container of evacuated vapor electric apparatus so that, when the vacuum becomes too high, a small amount of gas may be admitted for regulat- 1ng purposes. Carbon has been commonly employed for this purpose hitherto, and reliance has been placed upon a ground fit between the plug and the wall of the container. By constructing the porous plug of alundum, however, I may seal it directly into the wall of a glass container and thus obtain very effective gas-feeding operation, the possibility of leaks between the wall of the contalner and the plug being greatly reduced.

Referring to the form of my invention shown in the drawing, a container 1, composed, preferably, of sodium-borosilicate glass,is submerged in oil contained in a suitable tank 2. The container 1 is provided with an anode 3 and with a main cathode 4 of the usual type, current being supplied to the former by a lead 5 and taken from the latter by a lead 6. The device may be started, and maintained in operation, by a suitable auxiliary anode 7 supplied with current by a wire 8. With a rectifying device of the character described, the cathode blast emanating from the electrode 4 mechanically entrains particles of mercury them upon the anode 3, brea ing down the negative-electrode reluctance of the latter and causing the short circuiting of the device. I therefore interpose a disk of alundum 9 between the anode 3 and the cathode 4t and support said disk in any suitable manner, as, for example, by inwardly projecting lugs 10'formed on the container wall. By this construction, the arc is forced to flow in the annular space between the edge of the disk 9 and the wall of the container, and mercury particles from the cathode are therefore prevented from be1ng pro ected upon the anode 3. The mechamcal fit beand projects tween the disk 9 and the lugs 10-10 may be so close that rattling of the disk 9 is prevented, as I have found that the similarity in the coefficients of expansion prevent the development of abnormal strains. The disk 9 is so refractory in nature that little or no deterioration takes place therein, even though an arc of great magnitude plays over the edge thereof for a long period of time.

A porous plug 11 is sealed in the end of a tubulature 12 formed on the container 1, and the flow of gas therethrough is regulated by any suitable means, such, for example, as a 001 of'sealing fluid 13. The level of the liquid inthe pool 13v may be regulated by a plunger 15, actuated by the core 16 of asolenoid 17 to expose more or less of the plug 11, as described in U. S. Patent No. 820,364, granted May 8,1906, to D. McF. Moore.

While I have illustrated the use of alun- 1 dum in the form of a flat baffle plate, Iwish it to be distinctly understood that I contemplate its use as a substitute for iron or glass ,in any of the Well known shielding systems of the prior art, as I find that its general characteristics are such as to specially adapt it to this class of service. I do not desire, therefore, to be limited to the structure shown, but desire that only such limitations shall be, placed upon my invention as are imposed by the prior art or are set forth in the appended claims.

I claim as my invention: 1. An arc shield for use in an evacuated space and composed of alundum.

2. An arc shield for use in an evacuated space and composed essentially of alundum.

3. The combination with a container composed of glass having a coefficient of expansion of substantially .00036, of a member composed of alundum and closely engaging of a member closely engaging the wall thereof at'a plurality of points and composed essentially of alundum.

6. In vapor electric apparatus, the combi nation with a container composed of glass having a coefficient of expansion of substantially .00036 per degree centigrade, of a plurality of electrodes therein, and a baffle plate between said electrodes composed essentially of alundum.

7. In vapor electric apparatus, the combination with a container composed of sodium bore-silicate glass, of a plurality of electrodes therein, and a baffle plate between said electrodes composed essentially of alundum.

8. In vapor electric apparatus, the combination with a container composed of glass having substantially the same coefficient of expansion as tungsten, of trodes therein, and a ba e plate between said electrodes composed essentially of alum dum.

9 In vapor electric apparatus, the combination with a glass container, of a plurality of electrodes therein, and an arc-shieldin member associated with said electrodes and composed essentially of alundum.

In testimony whereof, I have hereunto subscribed my name this 27th day of April, 1915.

HAROLD A. NEWCOMB.

afilplurality of elec- 

